diff --git a/ChangeLog b/ChangeLog
index 87a5044c2f..d20c69b0e5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Wed Jan 13 11:57:38 2010  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
+
+	* object.c (rb_class_initialize): Make sure BasicObject doesn't get
+	  initialized twice [ruby-core:27577]
+	
+	* class.c (rb_class_init_copy): ditto
+
 Wed Jan 13 06:54:44 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* configure.in: check for if struct timezone is defined.
diff --git a/class.c b/class.c
index 599cbd689e..6674ae1a9d 100644
--- a/class.c
+++ b/class.c
@@ -180,7 +180,7 @@ rb_mod_init_copy(VALUE clone, VALUE orig)
 VALUE
 rb_class_init_copy(VALUE clone, VALUE orig)
 {
-    if (RCLASS_SUPER(clone) != 0) {
+    if (RCLASS_SUPER(clone) != 0 || clone == rb_cBasicObject) {
 	rb_raise(rb_eTypeError, "already initialized class");
     }
     if (FL_TEST(orig, FL_SINGLETON)) {
diff --git a/object.c b/object.c
index 58ca4c1267..73e5bd12a2 100644
--- a/object.c
+++ b/object.c
@@ -1427,7 +1427,7 @@ rb_class_initialize(int argc, VALUE *argv, VALUE klass)
 {
     VALUE super;
 
-    if (RCLASS_SUPER(klass) != 0) {
+    if (RCLASS_SUPER(klass) != 0 || klass == rb_cBasicObject) {
 	rb_raise(rb_eTypeError, "already initialized class");
     }
     if (argc == 0) {